The bank card (BC) system allows payment to be made for the purchase of products or services. The credit authorization amount of each card depends on many factors such as the solvency of its owner, the type of contract between the owner of the card and the issuing bank, etc. The credit authorization limit thus varies according to the various types of cards and may involve considerable sums of money. Admittedly, this credit authorization limit offers the card holder the advantage of being able to make purchases for amounts that may be higher than the balance of his/her bank card at the time of the purchase. However, in the case of certain stolen or counterfeit cards, this system enables the thief or fraudulent individual to make several cash withdrawals or purchases on the card holder's account without there being a limit to the amount of withdrawals or purchases.
In order to avoid these drawbacks, an electronic purse (EP) system has been developed. This system allows a certain amount of money to be recharged and the purchase of products and services of an amount less than or equal to the sum of money remaining.
Generally speaking, electronic purses resemble traditional smart cards and thus consist of a plastic card body in which an electronic module is inserted and designed to be connected to a reader.
EPs are disposable or rechargeable. In the case of disposable EPs, the electronic module is essentially made up of a single memory whose contents, representing the available balance, is decremented by the amount of the transaction made each time it is used and until the balance remaining is zero. This type of electronic purse operates in exactly the same manner as a prepaid telephone card. The structure of the rechargeable EP is more complex as it features a rewritable memory in which a balance file is defined, the content of which is, as for the disposable EP, decremented after each transaction or, on the contrary, incremented by the amount of the sum recharged; all of these operations being controlled by a microprocessor and with a degree of security which does not exist in disposable EPs.
The rechargeable EP management system requires an acquisition and recharge system and a system which allows the circulation of the electronic money to be controlled. At present, existing EP systems require a new architecture in relation to the already existing bank card system. The EP management system requires a system which controls both electronic value acquisition and emission. Furthermore, the bank must be able to establish a daily log of the EP and thus to establish electronic value circulation traceability so that the difference between the balance of the emission system and the acquisition system are always positive or at least equal to zero, what is carried out by establishing a mirror account. The document EP 0.797.174 describes such management system by simplifying it since there is deletion of the account called “pool account”. However, this system has always the drawback of using a centralized management at the bank level.
In addition, a secure debit and credit system must be established at all levels, for which the main system consists in transferring money in a SAM (Security Application Module). The security module also acts at the emission level, acquisition and recharge systems and the recharge and payment terminals. Its installation requires that new modules, new software and new connections be established.
Existing bank card management systems are based on a simple collection and authorization system. Unlike the EP system, money does not circulate although a bank to bank compensation system is in operation. The compensation system consists in using an acquisition system to collect the individual transactions made on the withdrawal and payment terminals in stores, and then to transfer the money by conversion between the bank card holder's bank account and the shopkeeper's bank account. The authorization system consists in checking whether the card is “valid” and whether the cardholder is solvent. This scheme does not require the installation of a security module.
The EP systems currently developed are thus complex to implement as they require a new architecture in relation to the already-existing bank card system and a complex secure management system.